9322506 Gladstone The proposed work involves investigating the chemical response of the upper atmosphere and ionosphere of Jupiter in the aftermath of the impact of the comet Shoemaker-Levy 9. Specifically, after characterizing the chemistry of the comet prior to the collision, a time-dependent study will be conducted as to the effect on the abundances of observable hydrocarbons of an injection of cometary material into the jovian upper atmosphere. Investigators will also study the effect of injecting into the upper atmosphere substantial amounts of usually tropospheric species, such as ammonia, that might be entrained in a deep impact fireball. Finally, the changes in ionospheric composition in response to the event will be separately examined. ***